Many facilities, such as restaurants, have production processes which require the discharge of significant volumes of grease through roof-mounted discharge vents. The discharged grease may accumulate on the roof and cause deterioration of the roofing materials surrounding the grease discharge vent, including the flashing and gaskets associated with the vent installation. These roofing materials are typically organic materials which may deteriorate rapidly when exposed to grease. Certain grease filter assemblies are successful in absorbing or trapping the grease discharged from roof-mounted discharge vents.
Examples of such successful grease filter assemblies are disclosed in U.S. Pat. Nos. 5,512,073 and 5,567,216, issued to one of the same inventors as the present invention. These prior grease filter assemblies advantageously provided grease absorbing materials near the discharge vents using a support frame clamped to the duct in a manner that did not compromise the integrity of the duct, a requirement of many municipalities or governing bodies. By attaching to the duct, as opposed to the roof, the grease filter assembly is placed as close to the grease discharge vent as necessary to adequately absorb, trap, and filter the grease discharged from the vent. This prior grease filter assembly employs a universal frame structure for attachment and support so that it does not depend on a particular roof design or roof-duct configuration. This prior grease filter assembly also uses composite grease absorbing pads that are supported around the duct. This eliminates the need to cut the pad specifically to fit the duct.
There is now a desire to further address fire prevention measures for grease discharge assemblies. More specifically, the National Fire Protection Association publishes standards entitled “Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations,” which are also referred to as “NFPA 96.” NFPA 96 includes fire prevention standards for roof-mounted grease discharge vents. One of these standards requires a fire resistant barrier between the roof and any grease collecting device. Another standard requires that grease discharge vents be accessible and operable for cleaning. Therefore, there is a need for a grease filter assembly that further addresses additional fire preventative measures and standards.